Just some addition to the vac discussion. I have learned that rubber hoses on your gauge manifold can off gas. This means with no leak in the system a rubber hose can make it look like a leak. I tested this once and flared soft copper lines to replace my rubber hoses. Wow what a difference. Not that I do it every time but on critical equipment it can be the difference between searching for a ghost leak or packing up at 4 on Friday and going home.

Absolutely it can. Always keep your mic gauge hard piped to the system when doing a mic test, no hoses.

If I get a mic test to rise up above 500 and taper off below 2000, I suspect remaining moisture and generally assume I do not have a leak. If it goes above 2000 and won't stop, I begin leak checking

05-03-2013, 07:56 PM

beenthere

D1DR, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise, commentary or ask questions of the OP here.

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05-04-2013, 07:33 PM

brian.cornell

Its probably that his gauge hoses aren't holding the deep vacuum. Even the smallest of leaks in hoses due to bad seals will show up on the micron gauge. If he is so worried about it put nitrogen on it again and soap his welds instead of spending too much time watching the micron guage. Test it and move on.

05-05-2013, 10:29 AM

troyport

Well, he came back and pumped it down again. Got it to 137 microns and then it only bounced up to about 350 in 20 minutes. So, the charge was released, and the system is up and running!